Molecular sieve materials, both natural and synthetic, have been demonstrated in the past to be useful as adsorbents and to have catalytic properties for various types of hydrocarbon conversion reactions. Certain molecular sieves, such as zeolites, aluminophosphates, and mesoporous materials, are ordered, porous crystalline materials having a definite crystalline structure as determined by X-ray diffraction. Within the crystalline molecular sieve material there are a large number of cavities which may be interconnected by a number of channels or pores. These cavities and pores are uniform in size within a specific molecular sieve material. Because the dimensions of these pores are such as to accept for adsorption molecules of certain dimensions while rejecting those of larger dimensions, these materials have come to be known as “molecular sieves” and are utilized in a variety of industrial processes.
One of the zeolitic structure structures which occurs naturally is offretite. Naturally occurring offretite is rare, and it is known to produce offretite synthetically. For example, Great Britain Patent No. 1,188,043 discloses a synthetic aluminosilicate offretite type material and its synthesis in the presence of tetramethylammonium cations.
M. Itakura et al. (Mater. Res. Bull. 2010, 45, 646-650) report the synthesis of high-silica offretite (Si/Al molar ratio=7.6-8.0) by interzeolite conversion of faujasite in the presence of both benzyltrimethylammonium hydroxide and structure-forming alkali metal cations.
According to the present disclosure, high-silica OFF framework type zeolites can be synthesized using cyclopropyltrimethylammonium cations as a structure directing agent.